12 results on '"Smeets, M."'
Search Results
2. Automatic 3D dense phenotyping provides reliable and accurate shape quantification of the human mandible.
- Author
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Verhelst, Pieter-Jan, Matthews, H., Verstraete, L., Van der Cruyssen, F., Mulier, D., Croonenborghs, T. M., Da Costa, O., Smeets, M., Fieuws, S., Shaheen, E., Jacobs, R., Claes, P., Politis, C., and Peeters, H.
- Subjects
PHENOTYPES ,MANDIBLE injuries ,STANDARD deviations ,EUCLIDEAN distance ,INTRACLASS correlation - Abstract
Automatic craniomaxillofacial (CMF) three dimensional (3D) dense phenotyping promises quantification of the complete CMF shape compared to the limiting use of sparse landmarks in classical phenotyping. This study assesses the accuracy and reliability of this new approach on the human mandible. Classic and automatic phenotyping techniques were applied on 30 unaltered and 20 operated human mandibles. Seven observers indicated 26 anatomical landmarks on each mandible three times. All mandibles were subjected to three rounds of automatic phenotyping using Meshmonk. The toolbox performed non-rigid surface registration of a template mandibular mesh consisting of 17,415 quasi landmarks on each target mandible and the quasi landmarks corresponding to the 26 anatomical locations of interest were identified. Repeated-measures reliability was assessed using root mean square (RMS) distances of repeated landmark indications to their centroid. Automatic phenotyping showed very low RMS distances confirming excellent repeated-measures reliability. The average Euclidean distance between manual and corresponding automatic landmarks was 1.40 mm for the unaltered and 1.76 mm for the operated sample. Centroid sizes from the automatic and manual shape configurations were highly similar with intraclass correlation coefficients (ICC) of > 0.99. Reproducibility coefficients for centroid size were < 2 mm, accounting for < 1% of the total variability of the centroid size of the mandibles in this sample. ICC's for the multivariate set of 325 interlandmark distances were all > 0.90 indicating again high similarity between shapes quantified by classic or automatic phenotyping. Combined, these findings established high accuracy and repeated-measures reliability of the automatic approach. 3D dense CMF phenotyping of the human mandible using the Meshmonk toolbox introduces a novel improvement in quantifying CMF shape. [ABSTRACT FROM AUTHOR]
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- 2021
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3. Idarubicin DNA intercalation is reduced by MRP1 and not Pgp.
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Smeets, M E P, Raymakers, R A P, Vierwinden, G, Pennings, A H M, Boezeman, J, Minderman, H, de Witte, T M, Smeets, M E, Raymakers, R A, and Pennings, A H
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DRUG resistance , *GLYCOPROTEINS , *ANTINEOPLASTIC antibiotics , *CARRIER proteins , *CHEMICAL reagents , *COMPARATIVE studies , *DAUNOMYCIN , *ENERGY transfer , *FLOW cytometry , *FLUORESCENCE spectroscopy , *HETEROCYCLIC compounds , *RESEARCH methodology , *MEDICAL cooperation , *GENETIC mutation , *RESEARCH , *DNA-binding proteins , *EVALUATION research , *IDARUBICIN , *FLUORESCENT dyes , *CANCER cell culture , *PHARMACODYNAMICS - Abstract
Currently available data regarding the substrate specificity of the multi-drug resistance (MDR) mechanisms P-glycoprotein (Pgp) and MDR-associated protein (MRP1) for idarubicin are inconclusive. A multiparameter flow cytometry method was developed which allows simultaneous quantitative measurement of total cellular fluorescence and the amount of anthracyclines intercalated into the DNA. Anthracycline DNA intercalation was measured by fluorescence resonance energy transfer (FRET) between Hoechst 33342 and anthracyclines. Daunorubicin and idarubicin accumulation were studied and compared in established cell lines expressing Pgp and MRP1. The data demonstrate that daunorubicin DNA intercalation is affected by both Pgp and MRP1 whereas idarubicin DNA intercalation is affected only by MRP1. MRP1 and Pgp function could be blocked completely by 5 microM PAK 104P, while higher concentrations of verapamil, PSC 833 and cyclosporin A were necessary to attain complete blocking of MRP1 compared to Pgp. Daunorubicin DNA intercalation correlates better with cell survival and is more sensitive at physiological MDR expression as observed in hematopoietic progenitors than daunorubicin levels measured by total cellular fluorescence. In conclusion, idarubicin DNA intercalation is reduced by MRP1 but not by Pgp. PAK-104P is an effective modulator for both Pgp and MRP1 and may further improve idarubicin efficacy. [ABSTRACT FROM AUTHOR]
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- 1999
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4. Long-term treatment of transfusional iron overload with the oral iron chelator deferiprone (L1): a Dutch multicenter trial.
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Kersten, M. J., Lange, R., Smeets, M. E. P., Vreugdenhil, G., Roozendaal, K. J., Lameijer, W., Goudsmit, R., and Smeets, M E
- Abstract
We performed an open, nonrandomized, multicenter phase-II trial to evaluate the efficacy and toxicity of 1 year of treatment with the oral iron chelator deferiprone in 38 mainly nonthalassemic patients with transfusional iron overload. Initial serum ferritin varied between 996 and 11.644 micrograms/l. Patients were treated with 3-6 g of deferiprone daily. Mean urinary iron excretion (UIE) in 36 evaluable patients was 21.0 mg/24 h and was significantly higher in the patients with thalassemia than in those with myelodysplasia. Negative iron balance was achieved in 20 patients (56%). The median duration of treatment was 10 months; due to side effects and other causes only 20 patients completed 1 year of treatment. Mean serum ferritin levels decreased from 3563 micrograms/l at the start of the trial to 2767 micrograms/l at 6 months (26 patients, p < 0.004) and to 2186 micrograms/l at 12 months (20 patients, p < 0.005). Serum ferritin levels normalized in two patients who were no longer transfusion dependent. Deferiprone was clearly not effective in three patients (two with myelofibrosis, one with myelodysplasia). One patient with myelodysplasia developed agranulocytosis after 12 months of treatment; this was rapidly reversible after stopping deferiprone. Three patients had a mild and transient decrease in white blood cell count. Other side effects leading to withdrawal from the trial consisted mainly of nausea (3 patients), arthralgia (2), and skin rash (1). No clinical signs of zinc deficiency were seen, although zinc excretion was increased in three patients. No changes were seen in liver enzymes, creatinine, antinuclear factor, T-cell subsets, cardiac function, visual acuity, and audiogram. Although our results confirm deferiprone as an effective iron chelator in patients with thalassemia and in some patients with other forms of iron overload, there is still some concern about the safety of this drug, which therefore, at this time, should be used exclusively in well-controlled clinical trials. [ABSTRACT FROM AUTHOR]
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- 1996
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5. The low cycling status of mobilized peripheral blood CD34+ cells is not restricted to the more primitive subfraction.
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Croockewit, A J, Raymakers, R A P, Smeets, M E P, Bosch, G vd, Pennings, A H M, de Witte, T J M, Raymakers, R A, Smeets, M E, vd Bosch, G, Pennings, A H, and de Witte, T J
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HEMATOPOIETIC stem cell transplantation ,CELL cycle ,IMMUNOPHENOTYPING - Abstract
Mobilized peripheral blood progenitor cells (PBPC) have been shown to differ qualitatively from bone marrow (BM) progenitors. The released progenitor cells are predominantly in G0/G1 and show a relatively high percentage of rhodamine dull cells. Within the BM these last two features are characteristic of the more primitive progenitors. Although the mobilized PB cells can give rise to long-term repopulation and thus contain stem cells, the frequency of stem cells is not much higher if long-term initiating cell (LTC-IC) assays are used. To determine whether quiescent stem cells are selectively released or the low-cycle status of PB progenitors is related to the release from the BM microenvironment, the cell cycle status and rhodamine content in the PB and BM during mobilization were studied and compared with steady-state BM. More differentiated and more primitive progenitors were separated based on differentiation markers and cloned in single cell assay. In mobilized PB 54% of the CD34+ cells (n=5) were rhodamine dull compared to 22% in steady-state BM (P=0.014) [n=6]. The percentage of CD34+ cells in the S/G2M phases of the cell cycle was 2.1% in the mobilized PB (n=11), and 18% in steady-state BM (n=11) [P=0.002]. During mobilization the fraction of cells in the S/G2M phase of the cell cycle was 16% in BM (n=7), similar to steady-state BM (P=0.34). The released progenitors represented a selection of BM progenitors, with significantly more primitive progenitors (CD34+/13+/33dim) and less lymphoid precursors (CD34+/19+). Within the more differentiated CD34+113+/33bright, myelomonocytic precursors, both in PB as well as in BM, the percentage S/G2M was relatively higher than in the CD34+/13+/33dim subfraction: in normal BM: median 18% vs 8% (P=0.006) [n=8]; in mobilized PB 3% vs 2% (P=0.03) [n=10]; and in BM during mobilization 24% vs 7% (P=0.01) [n=6]. The cycle status of mobilized PB progenitors was low both in the primitive and more differentiated subfractions. During the mobilization period the BM progenitors are cycling as in steady-state BM. The low-cycle status of the mobilized PB progenitors may be related to the loss of contact with the micro-environment. [ABSTRACT FROM AUTHOR]
- Published
- 1998
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6. Vaginal cuff dehiscence in laparoscopic hysterectomy: influence of various suturing methods of the vaginal vault.
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Blikkendaal, M., Twijnstra, A., Pacquee, S., Rhemrev, J., Smeets, M., Kroon, C., and Jansen, F.
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Vaginal cuff dehiscence (VCD) is a severe adverse event and occurs more frequently after total laparoscopic hysterectomy (TLH) compared with abdominal and vaginal hysterectomy. The aim of this study is to compare the incidence of VCD after various suturing methods to close the vaginal vault. We conducted a retrospective cohort study. Patients who underwent TLH between January 2004 and May 2011 were enrolled. We compared the incidence of VCD after closure with transvaginal interrupted sutures versus laparoscopic interrupted sutures versus a laparoscopic single-layer running suture. The latter was either bidirectional barbed or a running vicryl suture with clips placed at each end commonly used in transanal endoscopic microsurgery. Three hundred thirty-one TLHs were included. In 75 (22.7 %), the vaginal vault was closed by transvaginal approach; in 90 (27.2 %), by laparoscopic interrupted sutures; and in 166 (50.2 %), by a laparoscopic running suture. Eight VCDs occurred: one (1.3 %) after transvaginal interrupted closure, three (3.3 %) after laparoscopic interrupted suturing and four (2.4 %) after a laparoscopic running suture was used ( p = .707). With regard to the incidence of VCD, based on our data, neither a superiority of single-layer laparoscopic closure of the vaginal cuff with an unknotted running suture nor of the transvaginal and the laparoscopic interrupted suturing techniques could be demonstrated. We hypothesise that besides the suturing technique, other causes, such as the type and amount of coagulation used for colpotomy, may play a role in the increased risk of VCD after TLH. [ABSTRACT FROM AUTHOR]
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- 2012
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7. Twenty-first century laparoscopic hysterectomy: should we not leave the vaginal step out?
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Twijnstra, A., Kianmanesh Rad, N., Smeets, M., Admiraal, J., and Jansen, F.
- Abstract
The objective of this study was to compare surgical outcomes for laparoscopically assisted vaginal hysterectomy (LAVH) with total laparoscopic hysterectomy (TLH) in three teaching hospitals in the Netherlands. This study is a multicenter cohort retrospective analysis of consecutive cases (Canadian Task Force classification II-2). One hundred and four women underwent a laparoscopic hysterectomy between March 1995 and March 2005 at one of three teaching hospitals. This included 37 women who underwent LAVH and 67 who underwent TLH. Blood loss, operating time, and intraoperative complications such as bladder or ureteric injury as well as conversion to an open procedure were recorded. In the TLH group, average age was statistically significant lower, as well as the mean parity, whereas estimated uterus size was statistically significant larger, compared to the LAVH group. Main indication in both groups was dysfunctional uterine bleeding. In the TLH group, mean blood loss (173 mL) was significant lower compared to the LAVH group (457 mL), whereas length of surgery, uterus weight, and complication rates were comparable between the two groups. The method of choice at the start of the study period was LAVH, and by the end of the study period, it had been superceded by TLH. LAVH should not be regarded as the novice’s laparoscopic hysterectomy. Moreover, with regard blood loss, TLH shows advantages above LAVH. This might be due to the influence of the altered anatomy in the vaginal stage of the LAVH procedure. Therefore, when a vaginal hysterectomy is contraindicated, TLH is the procedure of choice. LAVH remains indicated in case of vaginal hysterectomy with accompanying adnexal surgery. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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8. Cyclosporin increases cellular idarubicin and idarubicinol concentrations in relapsed or refractory AML mainly due to reduced systemic clearance.
- Author
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Smeets, M, Raymakers, R, Muus, P, Vierwinden, G, Linssen, P, Masereeuw, R, and de Witte, T
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GRANULOCYTE-colony stimulating factor , *MYELOID leukemia , *ANTINEOPLASTIC agents , *COMPARATIVE studies , *CYCLOSPORINE , *DAUNOMYCIN , *IMMUNOSUPPRESSIVE agents , *LONGITUDINAL method , *RESEARCH methodology , *MEDICAL cooperation , *RESEARCH , *DISEASE relapse , *PILOT projects , *EVALUATION research , *ACUTE diseases , *IDARUBICIN , *PHARMACODYNAMICS - Abstract
The feasibility of adding both the multidrug resistance modulator cyclosporin (CsA) and granulocyte colony-stimulating factor (G-CSF) to a standard salvage regimen of idarubicin (IDA) and cytarabine was evaluated in patients with resistant or relapsed acute myeloid leukemia and myelodysplastic syndrome. Three patients received IDA 12 mg/m2/day, the next four patients 9 mg/m2/day. The dose of CsA was 16 mg/kg/day. Six patients showed Pgp expression and none MRP1 expression. Grade III or IV toxicity (CTC-NCIC criteria) was registered in six patients for gastrointestinal, two patients for cardiovascular and one patient for neurological complications. Three patients died in hypoplasia and three patients showed leukemic regrowth. Three control patients were treated with IDA 12 mg/m2/day and cytarabine, but no CsA and G-CSF. The plasma IDA and idarubicinol (ida-ol) area under the curve's of patients treated with IDA 12 mg/m2 plus CsA were higher (P< 0.05) than in controls. Cellular IDA concentrations were almost similar, but cellular ida-ol concentrations were significantly higher (P < 0.05) in the presence of CsA than in controls. We conclude that the toxicity either with IDA 12 or 9 mg/m2/day was too high. The modulating effect of CsA was mainly based on changes in plasma kinetics of IDA and ida-ol, although ida-ol cellular clearance was delayed in the presence of CsA. [ABSTRACT FROM AUTHOR]
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- 2001
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9. MR imaging in retinoblastoma.
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Barkhof, F., Smeets, M., Valk, P., Tan, K., Hoogenraad, F., Peeters, J., Valk, J., van der Valk, P, and Tan, K E
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We studied the appearance of retinoblastoma on unenhanced and gadolinium-enhanced images and the accuracy of tumour staging with MR imaging. The MR images were obtained in 18 children with retinoblastoma and compared with histopathological findings after enucleation. The MR imaging included T1-weighted and dual-echo T2-weighted images before, and T1-weighted images after, gadopentetate dimeglumine injection. The contrast between tumour and ipsilateral vitreous strongly increased (57 %) after gadolinium on T1-weighted images (p = 0.004). Tumour was strongly hypointense as compared with ipsilateral vitreous in all patients using heavily T2-weighted (TE = 120 ms) images (p = 0.001). The estimated T2 of tumour (mean 96 + 14 ms) did not correlate with histological grading or degree of calcification. Unenhanced T1-weighted MR images rightfully excluded extrascleral growth in 16 of 16 cases, but its presence was confirmed after enucleation in only one of 2 abnormal MR scans. Invasion of the optic nerve behind the cribriform plate was confirmed in 2 of 3 abnormal gadolinium-enhanced MR scans, but also in 1 of the 15 cases in which MR images were normal. The T2-weighted images were useful in assessing retinal detachment. We conclude that heavily T2-weighted images, unenhanced T1-weighted images and gadolinium-enhanced T1-weighted MR images are complementary in characterizing and staging retinoblastoma. [ABSTRACT FROM AUTHOR]
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- 1997
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10. Distinct levels of relationships between tospovirus isolates.
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Ávila, A., Haan, P., Smeets, M., Resende, R., Kormelink, R., Kitajima, E., Goldbach, R., and Peters, D.
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The taxonomic relations of a number of tospovirus isolates, collected in different geographical areas and from different host plants, were studied. To delineate these isolates, properties such as susceptibility of a limited range of host plants, symptomatology, cytopathology, nucleocapsid composition, serology of their nucleocapsid proteins, and nucleotide sequence homology were compared. The results show that isolates which have previously been discriminated as members of three different serogroups, should in fact be regarded as representatives of at least three distinct virus species in the tospovirus genus. [ABSTRACT FROM AUTHOR]
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- 1993
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11. The diagnostic and therapeutic approach of a primary bilateral leiomyoma of the ovaries: a case report and a literature review.
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Esch, E., Wijngaarden, S., Schaafsma, H., Smeets, M., and Rhemrev, J.
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OVARIAN tumors ,SMOOTH muscle tumors ,LAPAROSCOPY ,ABDOMINAL pain ,FROZEN tissue sections ,UTERINE fibroids ,ADNEXA uteri - Abstract
Introduction: A primary fibroid (leiomyoma) arising from both ovaries is rare and can be difficult to diagnose as a result of the low incidence and its indistinctive presentation. A literature review on the diagnostic and therapeutic approach of this rare benign tumour is presented. We describe a case of bilateral primary ovarian fibroid with an unusual presentation to illustrate our recommendations for treatment. Case presentation: A 37-year-old woman was admitted with symptoms of acute severe abdominal pain. She had a history of faint abdominal discomfort. Due to the acute deterioration of the abdominal pain a diagnostic laparoscopy was performed. A tumour arising from both ovaries was seen and a biopsy was taken in order to decide on further therapy. Histology showed a fibroid for which excision by a second laparoscopic intervention was planned. Due to excessive adhesions conversion to laparotomy was necessary. Conclusion: We recommend that in the case of an abnormal adnexal mass, particularly in women who want to preserve their fertility, frozen section histology be performed laparoscopically. A frozen section diagnostic procedure, instead of a regular biopsy, seems to be a useful tool during an elective diagnostic laparoscopic procedure in order to prevent potential morbidity as a result of possible future laparoscopy or even laparotomy. Previous laparoscopic procedures can cause massive adhesions that could impede a subsequent laparoscopic approach. [ABSTRACT FROM AUTHOR]
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- 2011
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12. Yersinia enterocolitica associated diarrhoea in a neonate.
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Jacobs, J., Smeets, M., Eggermont, E., and Vandepitte, J.
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- 1989
- Full Text
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